The orbital contribution can be represented by putting the charged ball at the carrousel. The center of the carrousel represent the nucleus, here we place the magnetometer to measure the magnetic field at the center of the carrousel. The charged ball is orbitting around the center of the carrousel. This generates a current which in turn generates a magnetic field.
The spin dipolar contribution can be represented by replacing the ball of the orbital contribution by a bar magnet.
The fermi constant contribution is represented by the child who places the charged ball closer to the center of the carrousel.